A good rule of thumb for the max amount of time a puppy can hold it in his crate without going potty is, the number of hours equal to his age in months. However, once a puppy is past 4 months old, you should never leave a puppy in a crate longer than 4 hours. Put yourself in the puppy's situation, how would you feel if you were stuck in a crate for more than 4 hours without the ability to go to the bathroom... it's just wrong to do, so don't do it to your puppy.
Keep in mind, you should always take a puppy out to potty right after he gets up from a nap/sleep, right after play time, and always after meals. A puppy will need to go to the bathroom outside while potty training at least 6 to 8 times a day if not more.