High Quality Content by WIKIPEDIA articles! The 5th season of the television series, Law & Order: Special Victims Unit premiered September 23, 2003 and ended May 18, 2004 on NBC. Law & Order: SVU moved away from its Friday night slot to Tuesday nights at 10:00 p.m. Eastern / 9:00 p.m. Central. Casey Novak, the unit`s longest serving ADA, was introduced in the fifth episode when Diane Neal joined the cast to fill the absence left by Stephanie March.