CREATE TABLE table_26816 ("Episode no." FLOAT, "Airdate" TEXT, "Viewers" FLOAT, "BBC Three weekly ranking" TEXT, "Cable rank" TEXT)

When 3 is the bbc three weekly ranking what is the airdate?
SELECT "Airdate" FROM table_26816 WHERE "BBC Three weekly ranking" = '3'
SELECT "Airdate" FROM "table_26816" WHERE "BBC Three weekly ranking" = '3'