userlist MySQL query

I have a table tg_user in my forum. It contains username, ID, and is_banned columns.

If a banned user creates a new account, they will still have the same ID, and I wish to find duplicates.

I wish to display a list of all users who have a banned ID, or share a banned ID with another user.

I don't wish to display all duplicate ID, only the ID that correspond to a banned account or have the same ID as a banned account.

is_banned is a 0 or 1 (unbanned or banned)