I started with a class C/D neighborhood, but I'm intentionally turning it into a Class B neighborhood, so I never had to deal with class D tenants.
Most class D neighborhoods have higher crime rates (putting your property at risk), low end tenants who are high risk of not paying their rent (why would a section 8 renter rent in class D when they can rent in class C?) and damaging your property, precisely because they are class D renters.
It might be better to invest a little more and be in a class C neighborhood, where you'll get better rents, have a little better class of renter, and less risk overall.
I know a lot of investors rent in class D neighborhoods, but the reality is it's usually a conveyor belt of renters, damages, fixes, rinse and repeat. Your property values really don't go up (and may well go down). Your rents are low and may go down as well.
You buy a 10k property in a crappy neighborhood and the amount of rehab you have to do is probably in the neighborhood of 60k- 70k or more (roof, furnace, wiring, plumbing, mold remediation and other things to bring it up to code). And the house won't be worth 30k when you're done with it. And think what type of person would want to rent that house (because even after putting 50-70k in it, it probably won't be all that pretty and the properties surrounding it certainly won't be)
At that point, you have 60-80k in it, and you can buy a 60-80k house in a different neighborhood that's better, put 50k into it because it's not as bad off as the other house, and have a house that's worth 100k+ when you're done with it. It will qualify for financing, and then section 8, or you can get tenants who are employed and will pay their rent on time.
If you want a 50k house that's not entirely crap in a bad neighborhood, Cleveland may not be the best market, just because the prices are high. (Also, my examples are more Youngstown than Cleveland because that's what I'm familiar with)