13.—(1) No member of the trade union shall be unreasonably excluded from standing as a candidate.
(2) No candidate shall be required, directly or indirectly, to be a member of a political party.
(3) A member of a trade union shall not be taken to be unreasonably excluded from standing as a candidate if he is excluded on the ground that he belongs to a class of which all the members are excluded by the rules of the union. But a rule which provides for such a class to be determined by reference to whom the union chooses to exclude shall be disregarded.