CREATE TABLE table_name_68 (elevation_groundstation INTEGER, slope_length VARCHAR(255), capacity_in_persons_hour VARCHAR(255), name_or_route VARCHAR(255))
Which elevation groundstation has a capacity in persons/hour larger than 820, and a Name or route of lager 1, and a slope length smaller than 336?
    
SQL: SELECT AVG(elevation_groundstation) FROM table_name_68 WHERE capacity_in_persons_hour > 820 AND name_or_route = "lager 1" AND slope_length < 336