What day was the margin of victory 1 stroke when the tournament was colonial national invitation?
CREATE TABLE "pga_tour_wins_5" (
  "date" text,
  "tournament" text,
  "winning_score" text,
  "margin_of_victory" text,
  "runner_s_up" text
);
SELECT "date" FROM "pga_tour_wins_5" WHERE "margin_of_victory"='1 stroke' AND "tournament"='colonial national invitation';