I use the term 'cover' as the costs of legal defence are often covered under an insurance policy and 'verweerbijstand' is also used in the context of legal defence insurance. However, I don't see anything essentially wrong with 'legal defence assistance', although I might be inclined to think of it as a translated term rather than a natural English one.

Dutch reference:
-> "LEGAL DEFENCE ASSISTANCE
Legal defence assistance against claims from third-parties alleging contamination, either actual or alleged, in respect of the insured’s liability for losses incurred by said third-parties outside the insured location."
http://www.eurolloyd.nl/milieuschade/milieublad_en.html

-> "Sports and recreational facilities will defiantly [sic] want to have a Comprehensive General Liability (CGL) Policy to cover legal defence costs and court awards they become legally obligated to pay in the event they are sued by a third party."
http://www.ucalgary.ca/MG/inrm/industry/sportsfacilities/lia...

-> "Legal Defence - Provides legal costs and expenses for defence and appeals in respect of civil and criminal proceedings for both you and your employees."
http://www.sjdaccountancy.com/about/policies/ourservices_pro...