You have two events:
A: pick an ace
B: pick a club
A suffled standard has: 52 cards.
4 aces
13 clubs
As the events A and B are not mutually exclusive (can happen at the same time) the probability is:
Probability of A: #aces/#cards = 4/52
Probability of B: #clubs/#cards = 13/52
Probability of A and B: #ace clubs/#cards = 1/52
Then the probability of pick an ace or a club is:
Then, the probability is 4/13