The current holder of the family title (or one of them)

It is commonly known that Sir Winston Churchill was the grandson of John Winston Spencer-Churchill, 7th Duke of Marlborough. So who is the current holder of the title? Charles James Spencer-Churchill, the 12th Duke. 

If you want his title in full, it is (are you ready for this?) "The most high, potent and noble prince His Grace Charles James Spencer-Churchill, Duke of Marlborough, Marquess of Blandford, Earl of Sunderland, Earl of Marlborough, Baron Spencer of Wormleighton, Baron Churchill of Sandridge." Evidently he is somewhat of a black sheep, having served jail terms on at least two occasions.