CREATE TABLE table_203_823 (id NUMBER, "model name" CLOB, "date" CLOB, "type" CLOB, "thrust  ( kg )  / power  ( eshp ) " CLOB, "fitted to" CLOB)

what was the top thrust achieved by a lyul ` ka engine before 1980 ?
SELECT "thrust (kg) / power (eshp)" FROM table_203_823 ORDER BY "thrust (kg) / power (eshp)" DESC LIMIT 1
SELECT "thrust (kg) / power (eshp)" FROM "table_203_823" ORDER BY "thrust (kg) / power (eshp)" DESC FETCH FIRST 1 ROWS ONLY