CREATE TABLE table_28171 ("No." FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" TEXT, "U.S. viewers  ( million ) " TEXT)

Who directed the episode that had a production code of 2j5457?
SELECT "Directed by" FROM table_28171 WHERE "Production code" = '2J5457'
SELECT "Directed by" FROM "table_28171" WHERE "Production code" = '2J5457'