returns on Monday for the fourth week of competition, and the stars are getting emotional for «Top 13 Night.»After the season's second elimination last week, the 13 celebs who are still standing — along with their pro partners — will be duking it out for the mirrorball trophy when they hit the stage and reflect on emotional, important and formative moments from their pasts.As Carrie Ann Inaba, Derek Hough and Bruno Tonioli judge and score the performances — and new host Tyra Banks adds her own