who is the runner-up when the winning score is −16 (68-70-65-65=268)?
CREATE TABLE "pga_tour_wins_5" (
  "date" text,
  "tournament" text,
  "winning_score" text,
  "margin_of_victory" text,
  "runner_up" text
);
SELECT "runner_up" FROM "pga_tour_wins_5" WHERE "winning_score"='−16 (68-70-65-65=268)';