Title: 1920–21 Northern Football League
Content:  The 1920–21 Northern Football League season was the 28th in the history of the Northern Football League, a football competition in Northern England.
Title: 1921–22 Northern Football League
Content:  The 1921–22 Northern Football League season was the 29th in the history of the Northern Football League, a football competition in Northern England.
Title: 1920–21 Northern Rugby Football Union season
Content:  The 1920–21 Northern Rugby Football Union season was the 26th season of rugby league football.
Title: 1923–24 Northern Football League
Content:  The 1923–24 Northern Football League season was the 31st in the history of the Northern Football League, a football competition in Northern England.
Title: 1922–23 Northern Football League
Content:  The 1922–23 Northern Football League season was the 30th in the history of the Northern Football League, a football competition in Northern England.
Title: 1920–21 Northern Football League
Content: Tow Law Town ; Langley Park The league featured 12 clubs which competed in the last season, along with two new clubs:
Title: 1924–25 Northern Football League
Content:  The 1924–25 Northern Football League season was the 32nd in the history of the Northern Football League, a football competition in Northern England.
Title: 1890–91 Northern Football League
Content:  The 1890–91 Northern Football League season was the second in the history of the Northern Football League, a football competition in Northern England.
Title: 1925–26 Northern Football League
Content:  The 1925–26 Northern Football League season was the 33rd in the history of the Northern Football League, a football competition in Northern England.
Title: 1920–21 Northern Football League
Content: show_limit=5 ; winpoints=2 ; use_goal_ratio=y ; res_col_header=PR team1=BIS|name_BIS=Bishop Auckland ; team2=STO|name_STO=Stockton ; team3=CRO|name_CRO=Crook Town ; team4=SBA|name_SBA=South Bank ; team5=WIL|name_WIL=Willington ; team6=DRA|name_DRA=Darlington Railway Athletic ; team7=TOW|name_TOW=Tow Law Town ; team8=LAN|name_LAN=Langley Park ; team9=ESH|name_ESH=Esh Winning ; team10=EST|name_EST=Eston United ; team11=STA|name_STA=Stanley United ; team12=GSM|name_GSM=Grangetown St. Mary's ; team13=RED|name_RED=Redcar ; team14=SCA|name_SCA=Scarborough win_BIS=19|draw_BIS=5|loss_BIS=2|gf_BIS=71|ga_BIS=24 ; win_STO=18|draw_STO=3|loss_STO=5|gf_STO=57|ga_STO=43 ; win_CRO=15|draw_CRO=4|loss_CRO=7|gf_CRO=58|ga_CRO=39 ; win_SBA=14|draw_SBA=6|loss_SBA=6|gf_SBA=48|ga_SBA=38 ; win_WIL=14|draw_WIL=3|loss_WIL=9|gf_WIL=52|ga_WIL=43 ; win_DRA=13|draw_DRA=2|loss_DRA=11|gf_DRA=43|ga_DRA=39 ; win_TOW=11|draw_TOW=7|loss_TOW=8|gf_TOW=50|ga_TOW=32 ; win_LAN=8|draw_LAN=7|loss_LAN=11|gf_LAN=53|ga_LAN=48 ; win_ESH=9|draw_ESH=5|loss_ESH=12|gf_ESH=39|ga_ESH=39 ; win_EST=7|draw_EST=8|loss_EST=11|gf_EST=43|ga_EST=51 ; win_STA=8|draw_STA=3|loss_STA=15|gf_STA=51|ga_STA=56 ; win_GSM=6|draw_GSM=2|loss_GSM=18|gf_GSM=30|ga_GSM=75 ; win_RED=5|draw_RED=4|loss_RED=17|gf_RED=22|ga_RED=58 ; win_SCA=4|draw_SCA=3|loss_SCA=19|gf_SCA=28|ga_SCA=60 adjust_points_TOW=-2|hth_TOW=Tow Law Town deducted two points for a breach of rule. col_R=#FFCCCC|text_R=Left the league ; result12=R ; class_rules=1) points; 2) goal ratio. ; update=complete|source= {{#invoke:sports table|main|style=WDL    }}

Question: What sport does 1920–21 Northern Football League play?
Answer: association football.
football.
soccer.