501 is the style
0126 is the color
32x34 is the size in inches waist x inseam
Levi's still sell non-stretch 501, and they should fit pretty much the same (although there is a lot more variation from one batch to the next than there used to be). If you can order from Levi's online you should be able to get similar ones. Or check any shops for 501 32x34 in 100% cotton.
Another option would be to get the original 501 shrink-to-fit (color 000). It's a process to break them in (not as much as heavier denim), but they should last longer since they're not stonewashed or otherwise treated to make them soft. Just read up on sizing first.