Harpo Prods. has tapped Joseph C. Terry as director of “The Oprah Winfrey Show.”TV’s top-rated talkshow is heading into its 12th season next month, amid questions about how many more years Winfrey will reign in daytime. Winfrey’s deal with distributor King World Prods. is up at the end of the coming season, and she has until Sept. 15 to let the Kings, and the rest of the world, know if she plans to continue her show. In the meantime, Harpo insiders say the company is firmly focused on staying on top in the coming season. “Oprah” still leads the daytime yak pack by a mile. “The Rosie O’Donnell Show” emerged last year as a potential challenger to “Oprah’s” dominance, although “Rosie’s” ratings have dipped in recent weeks. As the new director of “Oprah,” Terry succeeds Duke Struck, who served three years with the Chicago-based production. Terry spent the past six years as director of Paramount’s syndie talker “Maury Povich.” He previously served stints as a director and producer with CBS News, WABC New York, KCBS Los Angeles and WPVI Philadelphia.