What is the minimum number for the half marathon (womens)?
CREATE TABLE "winners_by_country" (
  "country" text,
  "total" real,
  "marathon_mens" real,
  "marathon_womens" real,
  "half_marathon_mens" real,
  "half_marathon_womens" real
);
SELECT MIN("half_marathon_womens") FROM "winners_by_country";