During what conference is North Carolina listed as the tournament winner?
CREATE TABLE "conference_winners_and_tournaments" (
  "conference" text,
  "regular_season_winner" text,
  "conference_player_of_the_year" text,
  "conference_tournament" text,
  "tournament_venue_city" text,
  "tournament_winner" text
);
SELECT "conference" FROM "conference_winners_and_tournaments" WHERE "tournament_winner"='North Carolina';