What was the margin of victory at the LPGA Championship?
CREATE TABLE "lpga_tour_wins_31" (
  "date" text,
  "tournament" text,
  "winning_score" text,
  "margin_of_victory" text,
  "runner_s_up" text
);
SELECT "margin_of_victory" FROM "lpga_tour_wins_31" WHERE "tournament"='lpga championship';