I believe that 'Brackens Brown Beauty' or 'Edith Bogue' would take your zone just fine.

The two varieties that laceyvail mentioned have good cold hardiness, but depending on where in SW Ohio you'll probably need to site it in a protected location. In general, the farther north you are from the Ohio River, the more protection it will need. Dawes Arboretum (east of Columbus) is growing several varieties successfully, but their climate is a bit milder than W/SW Ohio.

Missouri Botanical Garden says, "'Little Gem' is winter hardy to USDA Zone 7. It is not considered reliably winter hardy in the St. Louis area. If grown in St. Louis, it should be sited in a protected location (e.g., southern side of a building) that is sheltered from wind. May become somewhat deciduous in hard winters."

If you receive any winter snow at all, 'Little Gem' is not the cultivar you want to be growing, even if sufficiently hardy. And it is not.

For extended cold hardiness (-13F, zone 6a), look for 'Victoria'. This is also one of the very few cultivars of southern magnolia that can tolerate snow loads without extensive damage.

Thank you everyone so much for your input! I will look into these possible options. I really appreciate you all taking the time. Dawes Arboretum is about 110 miles east of me. I am a little south of Dayton.