Which Championship was louise suggs the runner-up by 3 strokes?
CREATE TABLE "wins_13" (
  "year" real,
  "championship" text,
  "winning_score" text,
  "margin" text,
  "runner_s_up" text
);
SELECT "championship" FROM "wins_13" WHERE "runner_s_up"='louise suggs' AND "margin"='3 strokes';