thank you for your question. Hydrangeas in pots can survive in the winter with planning and care. Before there is a freeze, prune  back the old wood. If you bring them indoors don't over water or give too much sunlight.  It might be best to put in a dark garage with some minimal light, and wrap so the plant won't freeze. Hydrangea are for outdoor planting so think about planting it in the pot/in the ground during the early summer for next winter.

Thank you for your follow-up question. 

If you keep the plant at room temperature and keep watering it, it might not bloom again. 

If you want your hydrangea to bloom again, it needs a period of cool temperatures in order to induce re-flowering. This involves keeping it at temperatures of 35 to 60 degrees F for about six weeks. Before getting the pot ready to store, make sure it is well watered, and check occasionally. Even after above-ground growth has gone dormant, the roots continue to need a little water.  After the cooling period, the plant can be moved to a sunny room with night temperatures of 55 to 60 degrees F. Water it well and fertilize about every two weeks and it could flower about four months later.

Here are some links to more information about overwintering hydrangeas and other potted plants.  

https://ipm.missouri.edu/MEG/2018/3/hydrangea/

https://extension.illinois.edu/blogs/good-growing/2020-11-18-overwintering-potted-plants

https://lancaster.unl.edu/hort/articles/2004/pottedtreesshrubs.shtml