There are a lot of places that teach photography in the Washington DC area, but remember, what makes the place worth going to is the quality of instruction that you’ll get.
It’s not so much about the place, it’s more about the teachers in the place.
Different teachers have different ways of teaching.
You should work with a photography teacher that you feel you can learn from. It’s not just about what’s taught, it’s also about HOW it’s taught. If you can, talk with the teacher before signing up for the class.
The truth of the matter is that there is no “best place” and there is no “best teacher”.
Simply pick the best teacher for you, located in a place that you can go to.
Here are a couple of links link to help you choose the best photography class for you.
https://samdamico.com/questions-invest-photography-class
http://washington.cbslocal.com/top-lists/best-photography-classes-in-washington-dc/