I think you mean they haven't done much recently? There was Obamacare which was doing pretty good for a bill so poorly written. They might have done more had the Republicans state, right on tv, that they would fight Obama on ANY legislation and, after the first Obama midterms stuck to it through the rest of his tenure. This is why, incidentally, Jackass has been able to reverse so much that Obama did as he did it by fiat as he was not allowed to pass any legislation by the Republicans as per Don't Give an Inch Gingrich in the 90's
Anyway, Democrats, how about medicare, social security, medicaid, environmental stuff, etc. You know, all that stuff that the Republicans are trying, very hard, to get rid of (including their "tax break" which not only increased the debt bigtime, but also started the death of medicare and obamacare. My point was that the Dems have stuff they should be proud of and the Republicans have lies that they are proud of and little else. I could easily give you a list of Republican messes but see no sense in that as you either know or don't and if you don't its unlikely you want to know or care.
You can google something like "what have democrats done" to get lists (some good some bad)
Here are a couple (both are positive):http://www.liberaldatabase.com/35-things-democrats-have-done-for-the-middle-class/https://www.dailykos.com/stories/2010/9/27/905677/-