what is the total viewers where the date of first broadcast is 28 january 2010 and the episode number is 1?
CREATE TABLE "table1_12995531_3" (
  "series_number" text,
  "episode_number" real,
  "date_of_first_broadcast" text,
  "total_viewers" real,
  "series_average" real
);
SELECT MIN("total_viewers") FROM "table1_12995531_3" WHERE "date_of_first_broadcast"='28 January 2010' AND "episode_number"=1;