The host of the world's longest-running TV quiz show in which teams of high school students in the Washington area compete against each other says he's retiring.

Mac McGarry, host of the Saturday morning show "It's Academic", is stepping down after 50 years. McGarry will be replaced by WTOP-FM news anchor Hillary Howard, who has been hosting on a temporary basis throughout the season.

"It's Academic" tests brainy high school students' knowledge on an array of subjects. Among the competitors the show has attracted are Secretary of State Hillary Rodham Clinton; New York Sen. Charles Schumer; Pulitzer Prize-winning writer Michael Chabon; and political commentator George Stephanopoulos.

"It's Academic" has been recognized by Guinness World Records as the longest-running quiz show on television. The show airs on WRC-TV in Washington.