"You have a Midland accent" is just another way of saying "you don't have an accent." You probably are from the Midland (Pennsylvania, southern Ohio, southern Indiana, southern Illinois, and Missouri) but then for all we know you could be from Florida or Charleston or one of those big southern cities like Atlanta or Dallas. You have a good voice for TV and radio.
Mine showed heavier emphasis on the south and a close second was Pennsylvania. That makes sense considering 6 of my formative years were spent on the north east coast (as a yankee!). hee hee