Their phone number is 937-855-7255.
If you want to go in and explain what you want to do they are at 75 Walnut.
A lot of the issue will be the area zoning if it is in a commercial area you may have a problem but if it is residential or agg they may work with you.
You will probably need to consult with the city's planning and zoning board to see if this would be a possibility. If it's not zoned residential, then you probably wouldn't be able to live there. What is the current zoning? Is it in an area that the zoning could be changed? However, your best bet is to see what zoning says. They will be able to answer all of your questions.
Good luck to you,