Touchup paint will do the job by filling the scratch but it will always be noticeable. If you want it to go away the entire area will need to be sanded and repainted. That might involve just the molding if the damage is limited to that area.
There are a lot of "gimmicky" products out there claiming to fix scratches but I have had good luck with NuFinish Scratch Doctor. Good Luck.pics? how deep is it?
I remember seeing a diy using some paint and a tooth pick to fill in the scratch if its really deep. and some type of wet sanding and polishing was required.
It all depends on the how deep the scratch is, you could probably use a polish if its not to deep.