On what date was the handicap 8 st 12 lb?
CREATE TABLE "race_record" (
  "age" real,
  "date" text,
  "track" text,
  "race" text,
  "distance_miles" text,
  "jockey" text,
  "handicap" text,
  "field_no_horses" text,
  "place" text,
  "time" text,
  "prize_money" text,
  "sweepstake" text,
  "archer_s_winnings" text
);
SELECT "date" FROM "race_record" WHERE "handicap"='8 st 12 lb';