Perhaps you should have done more research than 5 seconds in Google.
Democrat donors are at the top of the list of reported donations because they are more likely to report their donations. The whole point of how the Koch brothers route their money, and money funneled through their network of PACs, "think tanks", etc., is to hide the fact that they are funding it, so that their organizations all sound like "independent" supports of the Koch agenda. So they route it through "non-profits" or by providing non-cash benefits (e.g. providing a free vacation / educational conference), and of course pumping a fortune into "independent" issue campaigns, which are unregulated and whose funding sources are largely unreported. And, of course, the un-reported money flow is much larger than the reported money flow.
And you really can't equate the two.
In terms of assets, the Koch Brothers have 20x as much as Soros. So that's not even close.
And in terms of tactics, the Soros' political donations are well documented and transparent - be is open about what he supports, and he lobbies and promotes it in an open fashion. The Koch Brothers' money flow is generally hidden, and goes to subversive organizations like ALEC that literally write legislation, give it to legislators, who they give free vacations and political donations to, and has them pass it, sometimes literally in the middle of the night behind locked doors so nobody can see what they're doing. So you can't equate their tactics.