What was the winning score in the u.s. women's open that was won by 5 strokes?
CREATE TABLE "wins_13" (
  "year" real,
  "championship" text,
  "winning_score" text,
  "margin" text,
  "runner_s_up" text
);
SELECT "winning_score" FROM "wins_13" WHERE "championship"='u.s. women''s open' AND "margin"='5 strokes';