You might want to take a look at the underside of your tank and try to find a date stamp. If it's dated after your bike was made it may have been replaced by Ducati under the recall they had back then over the issue. Unfortunately not as many owners took advantage of it as they could have. So it's probably original. At the time, use of ethanol in gasoline was still illegal in most of Europe. So Ducati wasn't really well informed on the issues it causes. Ethanol free is great if you can find it nearby. So far where I live, 87 octane is the best I've found. The car does great with it, but the Duc doesn't want any part of it.
I had issues with the tank swelling when I first got it. I drained it removed the pump, and let it dry out for a little more than a week or so. It helped significantly. Best thing of course is ride it regularly, sitting is what brings on the worst side effects. As the ethanol and gasoline separate rather quickly since they aren't even compatible chemically in the first place. The undiluted ethanol is what's most dangerous to plastics, seals, etc. Plus gasoline dislikes water. Ethanol loves it, and absorbs it rather quickly causing further issues. A simple stabilizer is a good option. I've tried a few, and so far I prefer the Lucas by far. It's green, in a clear bottle. I use it sparingly, perhaps an extra spoonful if I know I won't be riding much.