CREATE TABLE table_69074 ("Episode No." FLOAT, "Airdate" TEXT, "Total Viewers" FLOAT, "Share" TEXT, "BBC One Weekly Ranking" FLOAT)

What were the air-dates of the episodes before episode 4 that had a BBC One weekly ranking of 6?
SELECT "Airdate" FROM table_69074 WHERE "Episode No." < '4' AND "BBC One Weekly Ranking" = '6'
SELECT "Airdate" FROM "table_69074" WHERE "BBC One Weekly Ranking" = '6' AND "Episode No." < '4'