CREATE TABLE table_203_193 (id NUMBER, "ship name" CLOB, "in service" NUMBER, "project number" CLOB, "type" CLOB, "class" CLOB, "comments" CLOB)

how many years later was the sibir in service after the lenin ?
SELECT (SELECT "in service" FROM table_203_193 WHERE "ship name" = 'sibir') - (SELECT "in service" FROM table_203_193 WHERE "ship name" = 'lenin')
SELECT (SELECT "in service" FROM "table_203_193" WHERE "ship name" = 'sibir') - (SELECT "in service" FROM "table_203_193" WHERE "ship name" = 'lenin')