As the Ostrava Town Archives website is not available in English, I have prepared a short guide showing how to search for censuses there. Censuses from years 1900 and 1910 are currently available for browsing - no name fulltext, but the censuses are nicely sorted by house numbers - each house number has its own "folder", so you don't have to browse all census sheets to find the proper house number.
This is what you'll see when you get to the website. Click on Procházet a hledat (Browse and search) tab.
Four possibilities will appear - the last one, Operáty (censuses), is the one you are looking for. When you click on it, two years will appear - 1900 and 1910.
When you click on a year, it will show list of villages/town quarters which have the census for that year available.
The list of house numbers will appear when you click on the village name.
Have fun! :)