What is Women's Doubles, when Year is 2007?
CREATE TABLE "past_winners" (
  "year" real,
  "men_s_singles" text,
  "women_s_singles" text,
  "men_s_doubles" text,
  "women_s_doubles" text,
  "mixed_doubles" text
);
SELECT "women_s_doubles" FROM "past_winners" WHERE "year"=2007;