What is the lowest 2nd (m) when the points were larger than 251.6?
CREATE TABLE "bischofshofen" (
  "rank" real,
  "name" text,
  "nationality" text,
  "1st_m" real,
  "2nd_m" real,
  "points" real,
  "overall_fht_points" text,
  "overall_wc_points_rank" text
);
SELECT MIN("2nd_m") FROM "bischofshofen" WHERE "points">251.6;