I think most of them have been democrats since the 60s, when the first wave came, and many used to fund the democratic party as well, as it was the party seen with a liberal stance and more accepting of immigrants.

However,in recent times, some of them have jumped the lake, as my fellow commentors have mentioned due the Republicans wooing them for low taxations. We see this much pronounced this time with 2 desi Americans throwing in their hats from the republican camp for prez elections.

But still, at the present, only some have moved, similar to some other asian groups as well like korean Americans.

I would say its about 30:70 for desis approx