The phrase "a contention which" is correct and usable in written English.
It can be used when introducing a specific argument or point of view in a discussion or debate.
Example: "The author presents a contention which challenges the prevailing theories in the field."
Alternatives: "an argument that" or "a claim that".
Their position was that the particular contemptuous acts charged did not in fact have the effect of obstructing justice, a contention which cannot be urged here.
In any event, the claim is not that the second indictments did not carry adequate notice of the charges, which they obviously did, but that the notice came much too late, a contention which we have already disposed of.
The question of Mr. Kaczynski's competence arose on Thursday after he sought to represent himself and dismiss his lawyers, who wanted to base their defense on the assertion that he was mentally ill, a contention which he denies.
Games are not art because there is no individual ownership, he insisted at the time, a contention which appeared to strike out a whole pantheon of collaborative projects from art history.
Critics of the PCC regarded both groups - in company with Murdoch's organisation - as the behind-the-scenes string-pullers (and therefore controllers) of self-regulation, a contention which has always been hotly disputed by the industry.
Certainly no one discussed the rather odd allegation that he had copied a speech by British politician Neil Kinnock in the 80s -- a contention which, if true, would show bad judgment on a whole number of levels.
There is a faint contention, which we deem unfounded, that the petitioners were not given a fair hearing, and that there is no evidence to sustain the findings of the immigration official.
What Aldax does, exactly, is a source of contention which shines a light on the decline of traditional media in the United States and the role of corporate money in public life.
For they can have no desire of offerings from the unwilling, unless they are animated by a spirit of contention, which is a thing altogether undivine".
The current public discussion of race and the Academy Awards is a time of contention which may prove a time of clarification and of constructive new policies.
Consider the route, always a point of contention, which one might expect given that last year up to one million people crammed the narrow streets of Notting Hill.
