Name the guest 2 for colin murray 6 april
CREATE TABLE "table1_20466963_13" (
  "date" text,
  "presenter" text,
  "guest_1" text,
  "guest_2" text,
  "guest_3" text,
  "guest_4" text
);
SELECT COUNT("guest_2") FROM "table1_20466963_13" WHERE "presenter"='Colin Murray' AND "date"='6 April';