Question: During which season of the UK version of "The X Factor" did the group, who released the song "Black Magic", form?

Related documents: [0]  [DOC] "Black Magic" is a song by British girl group Little Mix. It was written by Camille Purcell, Ed Drewett, Edvard Forre Erfjord, and Henrik Michelsen. The Norwegian production duo Electric, who previously worked on the group's second studio album "Salute" (2013), produced the single with Matt Rad, who is additional producer. It was released as the lead single from their third studio album, "Get Weird" on 21 May 2015. "Black Magic" received critical acclaim from critics, who praised its upbeat and catchy sound and compared it to songs from their debut album, "DNA" (2012). [END] 
[1]  [DOC] Little Mix are a British girl group formed in 2011 during the eighth series of the UK version of "The X Factor". They are the first and, so far, only group to win the competition. Following their victory, they signed with Simon Cowell's record label Syco Music and released a cover of Damien Rice's "Cannonball" as their winner's single. The members are Jade Thirlwall, Perrie Edwards, Leigh-Anne Pinnock, and Jesy Nelson. [END]  
Answer: eighth
eighth