The seal just happens to be stuck to the bearing. It comes right off. It's a disposable part, replaced every time it's removed. You, like many others asking for help, have neglected to give us any information about your car, so it's not possible to offer you the part number in our replies. Here's a link for the Porsche online catalog. If your car is newer than what is covered by this catalog, you can Google a bit and find the catalog you need.
Genuine Parts Catalogue - Classic Genuine Parts & Technical Literature - Porsche Classic - Dr. Ing. h.c. F. Porsche AG
BTW, you can order a CD copy of the catalog from Porsche, and it's very reasonably priced.
The Cap'n