You could use row_number()
to partition by
the first two characters of job name. What that does is hand out an incremental number to each row with the same first two characters. The row with number one will have the highest runtime:
select *
from (
select row_number() over (
partition by substr(job_name,0,2)
order by RunTime desc) as rn
, Job_name
, RunTime
from YourTable
) SubQueryAlias
where rn = 1