Actor David Duchovny, who is best known for his leading role in the “X Files” and who more recently starred in the Showtime series “Californication,” is in contract to purchase an apartment inside the Ardsley, an exclusive Central Park West co-op. The Ardsley, located at 92nd Street, has a mixed record when it comes to accepting celebrities. Barbra Streisand once had a penthouse there, but Mariah Carey was rejected by the board when she tried to buy Streisand’s apartment in 1999. The apartment that Duchovny is vying for is a 19th-floor corner unit that has views of the reservoir in Central Park, a fireplace and a terrace.  The three-bedroom, three-bathroom unit is listed for $6.25 million. The unit last sold in 2001 for $3.25 million.