What is the lowest # Of Episodes, when Date Released is "15 December 2011"?
CREATE TABLE "dvd_releases" (
  "season" text,
  "date_released" text,
  "num_of_episodes" real,
  "num_of_discs" real,
  "special_features" text
);
SELECT MIN("num_of_episodes") FROM "dvd_releases" WHERE "date_released"='15 december 2011';