If you are looking for a revision that is older than last sunday (that is when SEDE gets its refresh) you could use the following query ...
, userid as [User Link]
-- first get all rows for a single post
-- that reflect an edit
-- to guarantee the revision nr is correct
-- as it is dependant on the row_number
, row_number() over (order by creationdate asc) as rev
where postid = ##postid:int?3607053## -- 3607053
-- this works for wiki, for normal posts we need more magic
-- because we have title and tag records as well
and posthistorytypeid in (2, 5) -- initial body, edit body
) as main
where text like '%' + ##searchfor:String?represents less than 2## + '%'
... to find the occurrences of the offending line of text.
You find the postid in the url of your browser when you click on the history link.
Do notice that the text column of the PostHistory table contains markdown so if the text you try find has markdown in it you need to use that in your search phrase as well.