In a situation like this, it's best to drive right over the pothole. At the speed at which you're travelling, there will be little or no damage. Trying to avoid the pothole will take you off your lane get you involved in a fatal accident with other road users. There are a few things that come in the way of easy night driving. An unclean windshield and improperly focused headlights are the two of them.
Unfocussed headlights pose an awkward glare to oncoming vehicles.
An unclean windshield only makes it worse if you're on the receiving end of the glare. Dust on the windscreen can break a single beam of light into a thousand blinding fragments. So a dusty windscreen can blind you completely every time a beam of light hits it. Remember that a clean windscreen can make a difference and it's important to maintain properly focussed lights at a low-beam level to avoid inconveniencing oncoming vehicles. However, while driving, it is important you do not look at the headlights of the oncoming vehicles.