This graph from Think Progress shows that Republican members of congress appeared on cable news way, way more often than Democrats this last Monday through Wednesday. That isn't a great deal of time, but it's telling that the GOP so outweighed Democrats during a period in which incredibly important and divisive legislation was on the line. And, hah, look at liberal MSNBC!
There are perfectly legitimate reasons for the disparity, of course. Conflict is better TV than compromise, so disagreeing with the President is more "newsworthy" than sticking with him. Furthermore bookers and producers at all those networks would probably tell you that they'd love to have Democrats on, but Republicans all return their calls faster. This is also a holdover from the 12 year period in which Republicans did control congress—the Republicans have more TV experience, more relationships with more shows and networks.
But, you know, those legitimate reasons are the stuff that ingrained institutional bias is made of. And so the complaints and politicking of a powerless minority are disproportionately treated as important and relevant, regardless of the fact that their only real strategy for solving America's problems right now is symbolic obstructionism.
(Also big lulz at Fox being the closest to balanced—conflict is good TV, of course their conservative hosts want to argue with liberals congress members!)