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Mano Negra held the title for 562 days , regularly defending it on EMLL 's main shows in Arena México , before losing the championship to Blue Demon on June 29 , 1975 .
 Mano Negra, Blue Demon
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Mano Negra, Blue Demon