As far as I know, it's the same as everyone else - if a reservation sits within the boundaries of a congressional district, that's who their representative is, and whichever state boundaries the reservation is within determines who their sebnators are. Not that the congressional delegations or senators give a damn about indian issues - unless the tribes have money to give, but that's pretty much true of politicians in general. We have it no diffeent in that regard.
The only real difference is, when individuals within the dominant culture resist tyranny, fight taxes, or struggle for property rights, they are called "patriots". When WE do the same, we are called something else...