The answer is complex, but most Televisions in RV's are designed for shore power use 120vac. Very few are designed for battery power (13.6, not 12) though as it happens some can be converted, very easily in fact (Quick trip to Radio Shack (while they last) is all that is needed. Once RS closes it's doors finding the proper plug will be a bit harder but there are still parts stores out there.
And some RV's have invertes, these convert 12-14 VDC to 120vac for use by the TV.
Finally: ALL televisions run on DC, voltage varies, but they all Run on DC, but that is INTERNALLY, what they plug into can be most anything.
Home is where I park it!