CREATE TABLE table_24068 ("Episode No." FLOAT, "Series No." FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Viewers  ( millions ) " TEXT, "Original airdate" TEXT)

Who directed episode number 23?
SELECT "Directed by" FROM table_24068 WHERE "Episode No." = '23'
SELECT "Directed by" FROM "table_24068" WHERE "Episode No." = '23'