Question: Which championship where Steve Agnew was relegated, is the second highest overall championship in the English football league system?

Context paragraphs:
Bayernliga: The Bayernliga (English: Bavarian league) is the highest amateur football league and the second highest football league (under the Regionalliga Bayern) in the state of Bavaria (German: "Bayern" ) and the Bavarian football league system.  It is one of fourteen Oberligas in German football, the fifth tier of the German football league system.  Until the introduction of the 3.  Liga in 2008 it was the fourth tier of the league system, until the introduction of the Regionalligas in 1994 the third tier.

EFL Championship: The English Football League Championship (often referred to as the Championship for short or the Sky Bet Championship for sponsorship reasons) is the highest division of the English Football League and second-highest overall in the English football league system, after the Premier League.  Each year, the top finishing teams in the Championship are promoted to the Premier League, and the lowest finishing teams are relegated to League One.

Isle of Man Premier League: The Isle of Man Premier League (also known as the Canada Life Premier League for sponsorship reasons) is the highest division of the Isle of Man Football League and the highest overall in the Isle of Man football league system.  The Premier League, which was introduced for the 2007–08 season, was previously known as the First Division.  Each year, the top finishing club is crowned league champion, and the two lowest placed clubs are relegated to Division Two.

National League System: The National League System comprises the seven levels of the English football league system immediately below the level of the English Football League.  It contains 86 league competitions and more than 1,600 clubs.  It comes under the jurisdiction of The Football Association.  The National League System has a hierarchical format with promotion and relegation between leagues at different levels.  For details of leagues above and below the National League System, see the English football league system.

Colchester United F.C. league record by opponent: Colchester United Football Club is an English professional football club based in Colchester, Essex, that was founded in 1937.  From the 1937–38 season, the club played in the Southern Football League until 1950, when they were elected to the Football League.  After playing in the Third Division South for eight seasons, Colchester remained in the Third Division when the league was re-organised by finishing 12th in 1958.  The club were relegated to the Fourth Division in 1961, but made an immediate return to the Third Division after finishing the 1961–62 season in second position, one point behind Millwall.  They bounced between the Third and Fourth divisions until 1990, when the club were relegated from the Football League for the first time in 40 years.  After two seasons in the Football Conference, the U's were promoted back to the Football League after winning the Conference title on goal difference over Wycombe Wanderers in 1992.  Colchester played in the Third Division between 1992 and 1998, when they won promotion to the Second Division after a play-off final win against Torquay United at Wembley.  The club remained in the third tier until 2006, as they were promoted to the Championship, the second tier of English football, for the first time in their history, ending the season as runners up in League One to Southend United.  The U's spent two seasons in the Championship, earning their highest-ever league finish of 10th position in the second tier before being relegated back to League One in 2008.  Following relegation to League Two at the end of the 2015–16 season, Colchester made a return to the fourth tier of English football for the first time in 18-years.

National League (division): The National League, currently named the Vanarama National League for sponsorship reasons, is the top division of the National League in English football.  It is the highest level of the National League System and fifth-highest of the overall English football league system.  While all of the clubs in the top four divisions of English football are full-time professional, the National League has a mixture of full-time and semi-professional clubs.  The National League is the lowest division in the English football pyramid organised on a nationwide basis.  Formerly the Conference National, the league was renamed the National League from the 2015–16 season.

List of Hayes &amp; Yeading United F.C. seasons: Hayes & Yeading United Football Club, an association football club based in Hayes, Hillingdon, England, was founded in 2007 as a result of Hayes and Yeading merging as one team.  In the 2006–07 Conference South the two teams finished in 19th and 16th respectively, so when they merged Hayes & Yeading United played in the same league the following season at level 6 in the English football league system.  In their second season they were promoted to the Conference Premier after winning the 2009 Conference South play-offs.  The club lasted three seasons in the Conference Premier before being relegated back into the Conference South.  For the 2015–16 season the division was renamed National League South; in the same season Hayes & Yeading finished in 21st place and were relegated for the first time to level 7 in the English football league system currently competing in the Southern Football League.

List of Sunderland A.F.C. seasons: Sunderland Association Football Club was founded in 1879 as Sunderland & District Teachers Association Football Club by James Allan.  They turned professional in 1885.  Sunderland won their first Football League championship in the 1891–92 season two years after joining the league.  They won the next Football League First Division on three occasions in four seasons; in 1892, 1893 and 1895, separated by a runner-up spot in 1894.  In the 1901–02 season, Sunderland won their fifth Football League First Division championship.  They came close to completing the "league and cup double" in the 1912–13 season, winning the league but losing to Aston Villa in the 1913 FA Cup Final.  The team's next success came in the 1935–36 season when they won the League Championship and also the Charity Shield.  They had not won the FA Cup until the 1936–37 season when they defeated Preston North End in the 1937 FA Cup Final.  Sunderland entered The Football League in 1890 and were not relegated from the top division until the 1957–58 season; a total of 58 seasons in the highest division of England.  Their next trophy came in the 1973 FA Cup Final as they beat Leeds United 1–0.  They reached the 1985 Football League Cup Final but finished as runners-up to Norwich City after being beaten 1–0.  In the 1986–87 season Sunderland were relegated to the Football League Third Division for the first time in their history under the management of Lawrie McMenemy, they however, returned to the second division the following season as champions–their lowest position in the English football league system.  Their first appearance in the Premier League came in the 1999–2000 season after being promoted as champions from Division One.  In winning promotion the club gained 105 points, which was a record at the time.  Sunderland gained just 15 points in the 2005-06 season, which set the record for the lowest number of points in a Premier League season, which has since been eclipsed by Derby County.

Sunderland A.F.C. league record by opponent: Sunderland Association Football Club, an English association football club based in Sunderland, Tyne and Wear, was founded in 1879.  They joined The Football League in the 1890–91 season replacing Stoke who had failed to be re-elected, making Sunderland the first new club to join the league since its inauguration in 1888.  Sunderland remained in the football league for 106 years, albeit in different divisions, until 1996 when they were promoted to the Premier League, which replaced the Football League's First Division at the top of the English football league system in 1992.  Since then the club has been relegated back into The Football League on four occasions.  They currently compete in the EFL Championship after relegation from the 2016–17 Premier League.

Steve Agnew: Stephen Mark Agnew (born 9 November 1965) is an English former professional footballer who was most recently the caretaker manager at Middlesbrough, who were relegated to the Championship during his tenure.

Supporting paragraphs: Steve Agnew EFL Championship
Answer: English Football League Championship