It's not the 13th that is causing the buzzing if it also buzzes a little on the 11th and 13th. With that scenario, the 14th would be the first place I'd look. As above, you need a straightedge to identify exactly where the high one is. And, yes, it is certainly possible for it to only be high (or problematically high) on that one string.
As far as solutions, they are many. The "correct" solution is to file down the high fret (requiring re-dressing the fret). This is best done by a pro unless you really want to invest in all the tools to do it right. If you do, there are lots of instructional videos that show you how. Otherwise, you can try raising the action just a little and/or add just a touch more relief with the truss rod. You may find that you can eliminate the problem with a small enough adjustment that you don't find it worth going to the trouble of the "correct" solution.
Oh, by the way, if you've just done a truss rod adjustment, give it a couple days to settle down before you worry about doing anything.
Originally Posted by IamJohn
I heard my mom tell my dad she didn't want me listening to his Frank Zappa records... so I listened to his Frank Zappa records.