where are custom Templates stored in the database?

I mistakenly crated a circular reference attaching 2 custom templates to each other. the system will not let delete either one because it being used by the other. Where can I delete this?

I don't have the answer to your specific question regarding the database, however I wanted to suggest perhaps you can create a temporary template, then reassign them to it so that the reference is no longer circular and you can delete them.

hope this is helpful!

Thank you for your willingness to help.
However,  I did stumble on the solution since. In the template list I clicked on the "Actions" drop down and found a way to reassign the correct base template without having to delete anything. This worked instantly!  This is proof I really am an idiot. The time I spent before finding this was insane.