Table: atlas_launch
Columns: date
time_gmt
serial
apogee
outcome

Question: What is the time (GMT) for the 4A Serial?
SQL: SELECT "time_gmt" FROM atlas_launch WHERE "serial" = '4a'

Question: What is the time (GMT) for the 12A Serial?
SQL: SELECT "time_gmt" FROM atlas_launch WHERE "serial" = '12a'