Who gets the tax deduction?

I took over the mortgage payments on a house Sub2.
The previous owner signed the deed over to me (and it was recorded)
and for the last 12 months I’ve been paying the mortgage, month in and month out while having a lease option tenant in the home.
Who gets the tax deduction?

depends on what the lease/option paperwork says.

definitely not the previous owner (although they will receive the 1098).
most likely you as the owner/lessor
possibly the tenant depending on the lease/option language.