To give you the most accurate "proper article" or usage context, could you tell me: Are you referring to a ? Is this for a legal, human rights, or news context ?

La Defensora del Pueblo, Nadia Cruz, participa en el Panel 6 "Los

Based on your request, the proper article or noun phrase depends on whether you are referring to a specific person, a formal title, or an institution. "La defensora" means "the defender" (female) in Spanish.