Who was the radio 1 presenter for the broadcast that had 9.73 million viewers? 
CREATE TABLE "episodes" (
  "episode" real,
  "broadcast_date" real,
  "bbc_one_presenter_s" text,
  "starring" text,
  "radio_1_presenter" text,
  "viewers_millions" text
);
SELECT "radio_1_presenter" FROM "episodes" WHERE "viewers_millions"='9.73';