Which Runner(s)-up has a Margin of victory of 1 stroke, and a Tournament of world seniors invitational?
CREATE TABLE "senior_pga_tour_wins_11" (
  "date" text,
  "tournament" text,
  "winning_score" text,
  "margin_of_victory" text,
  "runner_s_up" text
);
SELECT "runner_s_up" FROM "senior_pga_tour_wins_11" WHERE "margin_of_victory"='1 stroke' AND "tournament"='world seniors invitational';