What is Date, when Margin Of Victory is 4 Strokes?
CREATE TABLE "european_tour_wins_12" (
  "date" text,
  "tournament" text,
  "winning_score" text,
  "margin_of_victory" text,
  "runner_s_up" text
);
SELECT "date" FROM "european_tour_wins_12" WHERE "margin_of_victory"='4 strokes';