You shouldn't have to worry about that until you are in the Escrow phase:
However, if you want to avoid that complication;
you can contact a Title Company and befriend an Escrow Officer; have them do a Title Search.
If you are in an Escrow, and there is a lien, it usually has to be taken care of before the Escrow will close.
If it can't; you will have the option of dropping the deal.
Talk to your Realtor about your protections.
Good luck and may God bless