Ok well since ive been trying to re read GoF over and over I will try and answer...
I keep reading the first chapter than stopping for a week, then starting over again so yeah... lol anywho

I think that house is just abandoned now, since the old man who was the 'caretaker' for the house was killed I guess no one owns it now. Tom did live in that house when he wasnt at hogwarts im almost sure of it. Almost. And then he killed his parents got away with it changed his name and blah blah. So to answer, the Riddles owned the house while Frank was the gardener guy. Then the Riddles were killed and Tom is not in the picture anymore.... so I think that left Frank in charge... well since he took care of it no matter what, he lived in the other house right there the gardener house place. And so now he is killed and his wife dies later on... and now no one has it. Its right in a muggle neighborhood so i doubt the Malfoys would own it. And if they did, what use would it be to them. Grrr im so sorry if that was hard to understand I need to get off soon my eyes are all gittery lol.