WASHINGTON (Reuters) - The U.S. Department of Justice’s lawsuit aimed at stopping AT&T Inc from buying movie and TV show provider Time Warner Inc will be heard by District Court Judge Richard Leon, according to a court filing on Tuesday. Leon, who was nominated to the court by President George W. Bush, is no stranger to high-profile cases. In the 1990s, he worked on House of Representatives panels looking at the Iran-Contra affair and the Whitewater controversy. 