they are not deductible. while all the gains are tax-free when you take a distribution, the same goes for losses - they are 'tax-free' (i.e. not deductible).
It was a misc deduction on schedule A. Only an answer to a trivia quiz now.
Disclaimer: Not a tax professional. Information gathered from internet links. Anything dated in June 2019 was posted in prior years and is before the 2019 limits and changes.