You can use any veg you like-including a bit of potato. I'd use onions,carrot,celery, 1 potato-all cut into 1/4 inch dice-plus shredded greens such as cabbage,kale,chard or sprouts. Add any others that take your fancy.
I'd sweat the onion in olive oil along with several cloves of minced garlic,then add the veg,along with either several fresh,skinned diced tomatoes or 2 tins chopped, a tin of Borlotti,Cannellini or butter beans,about 2 litres of stock,and several handfuls of short shape tube pasta. Let simmer until the pasta is cooked,and season with salt and pepper.