CREATE TABLE table_name_4 (diameter__km_ INT, name VARCHAR, year_named VARCHAR)

Which Diameter (km) has a Name of alma-merghen planitia, and a Year named smaller than 1997?
SELECT MAX(diameter__km_) FROM table_name_4 WHERE name = "alma-merghen planitia" AND year_named < 1997
SELECT MAX("diameter__km_") FROM "table_name_4" WHERE "alma-merghen planitia" = "name" AND "year_named" < 1997