Which Regular Season Champion(s) has a Record of 9–0, and a Tournament Champion of north carolina?
CREATE TABLE "champions_by_year" (
  "year" text,
  "regular_season_champion_s" text,
  "record" text,
  "tournament_champion" text,
  "tournament_venue" text,
  "tournament_city" text
);
SELECT "regular_season_champion_s" FROM "champions_by_year" WHERE "record"='9–0' AND "tournament_champion"='north carolina';