As stated early in the thread, described in layman’s terms (and by a good number of doctors and what they toss you out of ER with) sciatica is a general phrase for low back/hip/down the leg pain*. Which exercises that are beneficial generally depend on the specific site of pain and actions that hurt/help the pain. I would suggest you see a physiotherapist.
*actual sciatica involve impingement of the sciatic nerve.