Question: What term is the current chairman of Prince William County serving?

Context:
Leven Powell
Leven Powell was born to William Powell and Eleanor (Peyton).
 Leven was born near Manassas in Prince William County, Virginia.
 He studied in private schools.
 He was deputy sheriff of Prince William County, Virginia, before he moved to Loudoun County in 1763, where he engaged in mercantile pursuits.
 He purchased a mill on Hunger Run and named it Sally Mill after his young wife, Sally.
 Sally Mill Road is between Aldie, Virginia and Middleburg, Virginia.
 A wall of the original mill still exists on the site.
 Leven later purchased 50 acres from Joseph Chinn who had built Chinn's Ordinary, now called the Red Fox Inn, in 1728 near the center of that 50 acre parcel.
 The area had been called Chinn's Crossroads, and was then known as Powell Town.
 When the town was officially established in 1787, Leven Powell declined to have the town named after him, so the name became Middleburgh, and later simply Middleburg.
Forest Park High School (Montclair, Virginia)
Forest Park Senior High School is a public high school in Montclair, Virginia, unincorporated Prince William County, Virginia, United States.
 It is part of Prince William County Public Schools and is located on 15721 Forest Park Drive (formerly Spriggs Road; the name changed during 2005-2006 construction on Spriggs Road).
 The school's name references adjacent Prince William Forest Park, one of the largest national parks in the Washington metropolitan area.
Occoquan River
The Occoquan River is a tributary of the Potomac River in Northern Virginia, where it serves as part of the boundary between Fairfax and Prince William counties.
 The river is 24.7 mi long, and its watershed covers about 590 sqmi .
 It is formed by the confluence of Broad Run and Cedar Run in Prince William County; Bull Run, which forms Prince William County's boundary with Loudoun and the northerly part of Fairfax counties, enters it east-southeast of Manassas, as the Occoquan turns to the southeast.
 It reaches the Potomac at Belmont Bay.
 The Occoquan River is part of the Chesapeake Bay watershed.
 The name "Occoquan" is derived from a Doeg Algonquian word translated as "at the end of the water".
Prince William County Sheriff's Office
The Prince William County, Virginia Sheriff's Office was established in 1731 to provide law enforcement and jailers for the County.
 In 1970, the Board of County Supervisors established the Prince William County Police Department which assumed the primary responsibility for law enforcement.
 In 1982, the Prince William County Adult Detention Center opened and assumed the duties of jailers.
 The Sheriff is a constitutional office elected by the Prince William County, City of Manassas and City of Manassas Park to provide certain public safety services.
Belmont Bay
Belmont Bay is a body of water at the mouth of the Occoquan River between Fairfax and Prince William counties, Virginia.
 The bay covers about 1500 acre .
 The bay adjoins the Elizabeth Hartwell Mason Neck National Wildlife Refuge and Mason Neck State Park on the Fairfax County side and the Occoquan Bay National Wildlife Refuge in Prince William County.
 The bay was named for the home, "Belmont," which was built circa 1730 overlooking the bay by Catesby Cocke, who was the clerk of the Prince William County court.
 Belmont Bay is notable for sightings of bald eagles that nest and feed in the refuges and for the numerous Great Blue Herons.
 Belmont Bay is also a popular destination for pleasure boats.
 Summer weekends usually attract 40 to as many as 100 boats to this location.
Prince William County Courthouse
Prince William County Courthouse is a historic courthouse located at Manassas, Prince William County, Virginia.
 It was built in 1892-1893, and is a two-story, Romanesque style polychromatic brick building.
 It measures 52 feet by 60 feet and has a hipped roof.
 The front facade is symmetrical and features a projecting central bay forming a three-story clock tower topped with a cupola.
 The building was restored in 2000-2001.
 The county government moved to the building from the Brentsville Courthouse and Jail, and the building continued to be actively used as a county courthouse until 1984.
Corey Stewart (politician)
Corey Stewart (born August 1, 1968) is an American lawyer and politician from Minnesota currently serving his fourth term as At-Large Chairman of the Board of Supervisors of Prince William County, Virginia.
Brentsville District High School
Brentsville District High School is a public high school in Nokesville in unincorporated Prince William County, Virginia, United States, and part of Prince William County Public Schools.
 It is the only high school in Prince William County considered to be in a developing rural community.
Prince William Board of County Supervisors
Prince William County, Virginia is divided into seven magisterial districts: Brentsville, Coles, Gainesville, Neabsco, Occoquan, Potomac, and Woodbridge.
 The magisterial districts each elect one supervisor to the Board of Supervisors which governs Prince William County.
 There is also a Chairman elected by the county at-large, bringing total Board membership to 8.
 A Vice-Chairman and a Chairman Pro-Tem are selected by the Board from amongst its membership.
 The current Chairman is Corey A. Stewart, who previously served as the Occoquan District Supervisor.
 The current Vice-Chairman is Supervisor Peter Candland, the Gainesville District Supervisor.
Bull Run (Occoquan River)
Bull Run is a 32.8 mi tributary of the Occoquan River that originates from a spring in the Bull Run Mountains in Loudoun County, Virginia, and flows south to the Occoquan River.
 Bull Run serves as the boundary between Loudoun County and Prince William County, and between Fairfax County and Prince William County.

Answer: fourth term