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

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')