What was the released date of Polarium?
CREATE TABLE "i_que_ds" (
  "western_title" text,
  "chinese_title" text,
  "pinyin" text,
  "released_date" text,
  "genre" text,
  "game_modes" text
);
SELECT "released_date" FROM "i_que_ds" WHERE "western_title"='Polarium';