A newbie question about fortress defending

[Chazar]

...but nevertheless, the sieger still needs antoher turn to storm, right? I even believed that there would not be a siege at all and that the castle would change ownership instantaneously. Maybe I just check this when I get home, not that it matter much...

I mean, you always have a single, crippled, weakened, mindless strength-1 unit left so that the siegers have to break down the whole defense as usual...