I think you mean you can hear spirits? As in I don't think an ability would be limited to only demons. And if you are worried that a spirit or demon is too close, too attached, or connected to you I would recommend doing a cleansing, a banishing ritual, and then protection and shelving over yourself, and your home to prevent any other spirits from coming back.
If I whore you I would cast a circle around you're House a big circle might be a bit difficult but I find it worth it plus than you would have some spair magical energy hanging around might come in Handy
I agree with Whiteraven. How do you know it's a demon? He could be anything and also if you are worried you will come to harm do a protection ritual. If it doesn't want to hurt you you'll be fine and if it does at least you'll have taken some steps.
I have a spirit that's been following my family but he just causes a few little annoyances so we've never been worried.