CREATE TABLE table_30120 ("Episode #" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Originalairdate" TEXT, "Viewers  ( millions ) " TEXT)

Who directed the episode with 6.37 million viewers?
SELECT "Directed by" FROM table_30120 WHERE "Viewers (millions)" = '6.37'
SELECT "Directed by" FROM "table_30120" WHERE "Viewers (millions)" = '6.37'