How do I get a doctor that will deliver my child ?

So I’ve had two children before this pregnancy . I’m curious as to how I get a set doctor that will deliver my baby ? Both of my other children I had a set doctor and she was supposed to deliver but instead I had whom was ever on call and residents. Is that normal now a days . I always remembered my mother and grandmother saying they had they same doctor . 🤷🏽‍♀️