CREATE TABLE table_3983 ("Series #" FLOAT, "Season #" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" TEXT)

What original air date was the episode with production code of 5.05?
SELECT "Original air date" FROM table_3983 WHERE "Production code" = '5.05'
SELECT "Original air date" FROM "table_3983" WHERE "Production code" = '5.05'