Former Law & Order: SVU assistant district attorneys Stephanie March and Diane Neal are returning to the NBC drama for its 13th season, executive producer Warren Leight said today. March, who played ADA Alexandra Cabot during seven seasons, and Neal, who played ADA Casey Novak during six seasons, will appear an undetermined number of episodes. They join newly hired detectives Danny Pino and Kelli Giddish in the cast, which includes returnees Mariska Hargitay, Ice-T and Richard Belzer. The series will air in the fall Wednesdays at 10 PM.