Adobe only sells the current version as a download. That current version is 13. In another month, it will probably release version 14. At that time, 14 becomes the current version and the only one available from Adobe online.
Your greatest chance for finding Premiere Elements 12 still in stock would be online at a place like Amazon. But, do a Google search nonetheless for an authorized reseller who might have the version in stock.
Some of those searches say 12 and bring up 13 as you found out.