You have an alias in the wrong place.
SELECT account_name ,sum(total_balance) from transaction
where account_name IN('cash','a/r','supplies','prepaid','land','gold')
AS total_assets
ORDER BY account_name
should be
SELECT account_name ,sum(total_balance) AS total_assets
from transaction
where account_name IN('cash','a/r','supplies','prepaid','land','gold')
ORDER BY account_name