First, clean the beans and cut them into smaller pieces. Cook together with part of the savory in a saucepan with salted water (approx. 15 - 25 minutes, depending on the type of bean).
Peel the zucchini, cut in half, remove the seeds and cut into cubes of approx. 2.5 x 2.5 cm. Peel and dice the onion and garlic, the garlic very finely. Finely chop the remaining savory.
Heat olive oil in a saucepan and sear the onion, garlic and savory in it, add the tomatoes, bring to the boil and then add the zucchini cubes. Let it cook for about 15-20 minutes. The zucchini should still have some bite. Then add the beans without the cooking water and season with salt, pepper and sugar.
I always take my own tomato puree - see my recipe - Tomatoes preserved for the winter and then use the salt very sparingly when seasoning.