When did the Mixed double Women's singles of isabel rocha, from the year 1970, and a Women's doubles of isabel rocha ana margarida?
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 "mixed_doubles" FROM "past_winners" WHERE "women_s_singles"='isabel rocha' AND "year">1970 AND "women_s_doubles"='isabel rocha ana margarida';