When I look at my table, then I see that дверь ends with -ь and when I then look at the genitive singular for that ending, I see -я, so then according to my table I get дверя. Which is a bit confusing, because I got that row of endings from the following Wikipedia page, which also lists exceptions under the table. So perhaps дверь follows the declension pattern of an unlisted exception on Wikipedia?:
Russian grammar - Wikipedia, the free encyclopedia