I will say again, I see a normal 99 year old coin. I checked coppercoins and variety vista. They have no listing for 1919 DDO and I honestly don't see any doubling on your coin.
I see what you're talking about, the curved shiny line is a hit which happened to line up with the tail of the nine. The inside part I think is just gunk/dirt. I can see how it looks like it's doubling but if you zoom in, you'll see it's clearly a scratch. At least, that's how it looks to me.