Elisabeth Rohm — best known for her roles on TNT's Bull and the WB's Angel — will replace Angie Harmon as the Assistant District Attorney on NBC's Law & Order next season, a show rep now confirms. Rohm's character is described as "an extremely gifted, intelligent and aggressive young prosecutor with Harvard Law Review on her r&#233sum&#233 and aspirations beyond the District Attorney's office." She'll debut in the show's 12th season premiere in the fall.