iPhone 5s I want to have speaker ring when head...

iPhone 5s version iOS 11.0.1

When I plug in the headphones, the speakers no longer ring/sing with incoming calls. It used to ring both in headphones as well as the speakers. Before I was able to remove my headphones from my head, leaving headphones still plugged into the iPhone then go off to somewhere else, and still catch the ringing of the phone.

Why, help, and teach me. Thanks