Because he's a Beagle not a Lab I'm afraid.
Unless your Beagle is well trained in the recall (come) command or "wait" command they should NEVER be let off the lead. He didn't stop for you because you were kind of chasing him and he thought it was good fun. If you had turned round and run in the opposite direction he might have come after you. If you had acted all excited with treats and/or toys in your hands as you ran away from him you might have had even better luck at getting him back.
It's not really about leadership or respect in this instance. If a Beagle is off lead and runs away it's not because he doesn't respect you. It's simply because he is doing what beagles do and following his nose.
If you haven't already, teach him the basic commands of "come" "wait" and "stay". A well trained dog is more likely to view you as the leader than an untrained one. And NEVER let him off lead unless it's safe to do so.
