I keep catching Litwicks in the Celestial tower because I need a Flamebody/Magma armor Pokemon to hatch eggs with, and despite Flame body being listed as a natural ability for that Pokemon on Bulbapedia, out of more than ten captures I've had a grand total of zero that had the ability. Is the site wrong, or should I search someplace else?
You just have bad luck. Litwick has Flame Body.