I recommend new oil and a new filter, that it. This may sound a bit odd however, so many cubs get run forever without an oil change. The fact that you're changing it is a good thing. If you know what has been run in it in the past, continue to do so. If not, do what you believe is best. This topic has been beat to death numerous times. Again, that fact that the oil is actually being changed is the best thing you can do for your tractor. And if you're changing the oil, ALWAYS change the filter!
As an OE manufacture's rep in the truck part business for many years, I've seen a lot of filter testing and price should be the last thing to look at. If you are dedicated to tracking how many engine hours you run between oil changes and you just play around a bit with the tractor, the filter will not be that critical. However, if you work your tractor and tend to go a bit long between oil changes, the quality of the filter can have a huge effect of the amount of engine wear you have. Not that the quality of you oil does not come into play here, but some of these filters have half the amount of filter media that the oil runs though verses others which again can have a major affect on engine wear. From what I've seen in testing, I've decided to run Baldwin filters on all my equipment, including my cubs. The Baldwin filter for a cub is PT135