What is the broadcast date when 8.3 million viewers watched?
CREATE TABLE "serial_details_by_episode" (
  "episode" text,
  "broadcast_date" text,
  "run_time" text,
  "viewers_in_millions" text,
  "archive" text
);
SELECT "broadcast_date" FROM "serial_details_by_episode" WHERE "viewers_in_millions"='8.3';