As difficult as it was for mob boss Tony Soprano’s daughter Meadow to find a college to go to last season on the hit HBO series “The Sopranos,” so was it hard for the show’s producers to find a real college that would let them film scenes of Meadow at school this week. Which is how the crew of “The Sopranos” ended up at Manhattan’s Baruch College yesterday, after they had been turned down by Columbia University — which is where Meadow (Jamie Lynn Sigler) is meant to be studying — and New Jersey’s William Patterson University. “There was some concern about how Columbia might be portrayed in the script,” the university’s associate vice-president Virgil Renzulli told The New York Times. “Our mission is teaching and research, not being the backdrop for a TV show.” Especially for one featuring a Mafia princess. “The Sopranos” is scheduled to return to the air for its third season in March.