A pup learning to ask you to let him out can happen at various ages, depending on the pup, and how well you and he are communicating. It happens because he gives small signals, and you cue in on the signals and respond... thus he learns that he can ask.
That said, don't expect this anytime soon. Most dogs don't learn this until 5 or more months of age.
However, don't be dismayed as a dog can be well house trained without having this skill of asking to go out.
The house training is really about habit formation. Once a strong habit of pottying outside is established, the dog will be very reluctant to potty inside, even if he has not learned to ask to go out yet.
As far as "holding it" goes, this is more about a mature bladder than about learning a concept of "I should hold it." Again at what age a puppy's bladder matures varies. In my experience, male puppies take longer.
Your puppy, as I recall is still less than 3 months old, is that correct? So he is no where near having any sort of bladder capacity or communication skills. Count on having to manage the situation for a couple more months.
What I tell people is to keep score. Put a penny in a jar for every outside potty that you reward within 2 seconds with a treat. Take 5 pennies out of the jar for every accident the puppy has inside. When you get 2 or 3 dollars in your jar, you can begin to give the puppy a bit more freedom in the house, that is let him loose in one room, for a few minutes after he has pottied outside, but keep your eyes on him at all times.
The thing about the keeping score is it demonstrates how important prevention of accidents really is. House training is all about forming the right habits, which means the pup needs to practice the right habits. Every accident means he practiced the wrong habits, so prevention is the key, as is REWARDING outside potty events EVERY time.