No names to help you. You might look in the American Driving Society magazine the Whip for advertising to find a Trainer of horses and drivers. The Carriage Association also has a magazine, the Carriage Journal that has advertising to find such Trainers. Thirdly is the Driving Digest, with lots of advertising for all things related to Driving. There are good Amish trainers of horses in your area, but most are advertised in the local Amish magazines and word-of-mouth. All Amish are not created equal, so get references from folks they trained horses for. Ask to learn what methods and how horse will be worked as the training program. It might not suit your horse and you, so you keep on looking for another.
The CDE stuff is most likely to be found in the magazines. Such driving Trainers advertise where the audience they seek will read and find them.
Checking the ADS site, you can check for your State, find local driving Clubs to contact and ask for more information. Under Members on the top of the Home Page you find Regions. Ohio is in the Central region, so here is a link to those States and your Regional Representative. Go down the page to the list of States, click up Ohio, which should show the Clubs for you to find folks. Hope this is helpful.
http://americandrivingsociety.org/Members/Regions/Central.aspx