CREATE TABLE table_18045 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" FLOAT, "U.S. viewers  ( millions ) " TEXT)

Who directed the episode that originally aired on January 15, 2008?
SELECT "Directed by" FROM table_18045 WHERE "Original air date" = 'January 15, 2008'
SELECT "Directed by" FROM "table_18045" WHERE "Original air date" = 'January 15, 2008'