CREATE TABLE table_3518 ("Episode #" TEXT, "Season Episode #" TEXT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Prod. code" TEXT)

What is the number of air dates titled 'The Big Job'?
SELECT COUNT("Original air date") FROM table_3518 WHERE "Title" = 'The Big Job'
SELECT COUNT("Original air date") FROM "table_3518" WHERE "Title" = 'The Big Job'