Comment 2 for bug 1937293

Hi, thank you for taking the time to file a bug report.

After researching your issue, postgresql-12 is asking for the correct libpq5 version but your system seems that have more sources in which it finds an upper and not right version (13.3-1.pgdg20.04+1) that is not an ubuntu package indeed. We suggest you check your repos sources configuration to solve this. In case you'd like things to work cleanly, we suggest you to remove (or/and purge) all the third party sources and the packages installed from there (postgresql-13, at least) and then do a fresh install of postgresql-12 via apt.

Since it seems likely to me that this is a local configuration problem,
rather than a bug in Ubuntu, I am marking this bug as 'Incomplete'.

However, if you believe that this is really a bug in Ubuntu, then we would
be grateful if you would provide a more complete description of the problem
with steps to reproduce, explain why you believe this is a bug in Ubuntu
rather than a problem specific to your system, and then change the bug
status back to "New".

For local configuration issues, you can find assistance here:
http://www.ubuntu.com/support/community