It was not accepted when I wrote "den" before "femte" in this sentence: "Det är femte gången du ringer mig i dag." I do not see any structural difference between "den femte gången" and "det nionde huset". So, when do we use "den/det/de" before the ordinal numbers when they are followed by a noun, as well?

Since hus has the et on the end indicating "the," is there any special rule when you also use "det"? Seems like sometimes it's there and sometimes not.