Stomach pudge I would like to get rid of?

I have a line on my stomach, I guess from where I would wear my pants kinda low when I was real young, and I guess my stomach started to grow that way. Well, there is a line with a shadow and it makes me look bigger. I am 5'8" and 125lbs. I know its not a lot, but I swear 3' or me is nothing but legs. could anyone help? Exercise suggestions? Crunches aren't seeming to work... and I run, but it's not showing any change either... thanks.