That’s a tiny interior crack on the wheat stalk and crimping machine damage on 0. They’re not worth anything but that’s what they are. Here’s what that 0 is...
One way to tell it's die deterioration or machine doubling rather than true doubled die is that the mint mark is affected. In those days, unless I'm mistaken, the mint marks were manually applied after the die was created, so any true doubling would not affect the mint mark. There does appear to be a very minor die break in the wheat on the reverse, which is common.
