200672
On 11 July 1917 , he shot down an Airco DH .4 from No. 57 Squadron RFC over Ledgehem , Belgium for his first aerial victory .
 No. 57 Squadron RFC, Ledgehem
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 No. 57 Squadron RFC, Ledgehem