Question: Which Rugby tournaments does Brett Herron's team compete in?

Context paragraphs:
Rugby union in Guam: Rugby union in Guam is a minor but growing sport.  They are currently ranked 82nd by the IRB.  Although Guam is often considered part of Oceania, it tends to take part in Asian rugby tournaments.

World Open (snooker): The World Open is a professional ranking snooker tournament.  It had previously been known as the "Professional Players Tournament", the "LG Cup" and the "Grand Prix".  During 2006 and 2007, it was played in a unique round-robin format, more similar to association football and rugby tournaments than the knock-out systems usually played in snooker.  The knock-out format returned in 2008 with an FA Cup-style draw.  The random draw was abandoned after the 2010 edition.  Ding Junhui was the defending champion.

Ulster Rugby: Ulster Rugby (Irish: "Rugbaí Uladh" ) is one of the four professional provincial rugby teams from the island of Ireland.  They compete in the Pro14 and the European Rugby Champions Cup.  The team represents the Irish Rugby Football Union (IRFU) Ulster Branch, which is one of the four primary branches of the IRFU and is responsible for rugby union throughout the geographical Irish province of Ulster, comprising six counties in Northern Ireland and three counties in the Republic of Ireland.

Glasgow Warriors: Glasgow Warriors are one of the two professional rugby union sides from Scotland.  The team plays in the Pro14 league and in the European Professional Club Rugby tournaments.  In the 2014-15 season they won the Pro12 title and became the first Scottish team to win a major trophy in rugby union's professional era.

Riaan Viljoen: Riaan Viljoen (born 1 April 1983) is a professional South African rugby union rugby player, currently playing with Japanese Super Rugby side the Sunwolves and Top League West side NTT Docomo Red Hurricanes.  He was born in Carletonville, South Africa and his first tour with the Springboks was to France, Italy, Ireland and England in late 2009 where he played in two touring matches.  He signed with the Sharks for the 2012 and the 2013 Super Rugby tournaments.

Thames Valley Rugby Football Union: The Thames Valley Rugby Football Union (TVRFU) is the governing body of rugby union in the region of Thames Valley in the North Island of New Zealand.  Their senior representative team compete in the Heartland Championship.  Thames Valley Rugby Football Union was founded in 1921 when it broke away from the now defunct South Auckland Rugby Football Union.  The Thames Rugby Union, a sub-union that had remained affiliated with the Auckland Rugby Football Union, eventually joined the Thames Valley Union in 1951.

Rugby union in England: Rugby union in England is one of the leading professional and recreational team sports.  In 1871 the Rugby Football Union, the governing body for rugby union in England, was formed by 21 rugby clubs, and the first international match, which involved England, was played in Scotland.  The English national team compete annually in the Six Nations Championship, and are former world champions after winning the 2003 Rugby World Cup.  The top domestic men's club competition is the Aviva Premiership, and English clubs also compete in international competitions such as the European Rugby Champions Cup.  The top domestic women's competition is the Premier 15s.

Rugby union at the Summer Olympics: Rugby union has been a men's medal sport at the modern Summer Olympic Games, being played at four of the first seven competitions.  The sport debuted at the 1900 Paris games where the gold medal was won by the host nation.  It was subsequently featured at the London games in 1908, the Antwerp games in 1920 and the Paris games in 1924.  The United States is the most successful nation in Olympic rugby tournaments, having won the gold medal in both 1920 and 1924; France has the most medals, one gold (in 1900) and two silvers (in 1920 and 1924).

Vientiane Buffalos RUFC: The Vientiane Buffalos rugby football club (sometimes spelled "Buffaloes") was founded in 1998 by rugby union playing expatriates in the capital of Laos.  The club has grown gradually since then and is a full member of the Lao Rugby Federation (LRF).  As well as men's contact rugby (sevens, tens and fifteen-a-side), the club organises touch rugby tournaments involving women and children.  Members of the Buffalos have been instrumental in promoting the sport in Laos, setting up the LRF and establishing a Lao national team and other clubs to play against.

Brett Herron: Brett Herron (born 13 November 1993) is an Irish professional rugby union player who currently plays for Ulster.

Supporting paragraphs: Brett Herron Ulster Rugby
Answer: Pro14 and the European Rugby Champions Cup