What is Date, when Viewers is 4.4 million?
CREATE TABLE "ufc_on_fox_s_nielsen_rating" (
  "event" text,
  "date" text,
  "rating" text,
  "share" text,
  "viewers" text
);
SELECT "date" FROM "ufc_on_fox_s_nielsen_rating" WHERE "viewers"='4.4 million';