If you previously purchased /had a subscription to get the CD/download, you may be able to find it in your Downloads page. Weirdly, this is NOT in your Account info on turbotax.com. It is on shop.turbotax.com. You should see a copy of every year of the software that you bought. You should be able to still download it because i still see mine on my Downloads list as of April 29 2018. But it may or may not be the final version and it will probably not be able to update.
You may do well to call Intuit/Turbotax if you think you did buy 2013 because you should at least be able to get the software you bought.