CREATE TABLE table_18065 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT)

When did the episode directed by David Duchovny originally air?
SELECT "Original air date" FROM table_18065 WHERE "Directed by" = 'David Duchovny'
SELECT "Original air date" FROM "table_18065" WHERE "Directed by" = 'David Duchovny'