Table: bg_discography
Columns: year
u_s_hot_100
u_s_r_b
u_s_rap
album

Question: Which U.S. Hot has 13 as the U.S. R&B?
SQL: SELECT "u_s_hot_100" FROM bg_discography WHERE "u_s_r_b" = '13'

Question: What U.S. Rap has life in the concrete jungle as the album?
SQL: SELECT "u_s_rap" FROM bg_discography WHERE "album" = 'life in the concrete jungle'