HAVING

SELECT 
  nerc_region, 
  SUM (demand_loss_mw) AS demand_loss 
FROM 
  grid 
  -- Remove the WHERE clause
WHERE demand_loss_mw  IS NOT NULL
GROUP BY 
  nerc_region 
  -- Enter a new HAVING clause so that the sum of demand_loss_mw is greater than 10000
___ 
  ___(demand_loss_mw) > ___ 
ORDER BY 
  demand_loss DESC;