CREATE TABLE table_2780146_6 (no_x__g_kwh_ VARCHAR, hc__g_kwh_ VARCHAR)

What's the NO of the standard with HC of 1.23 g/kWh?
SELECT no_x__g_kwh_ FROM table_2780146_6 WHERE hc__g_kwh_ = "1.23"
SELECT "no_x__g_kwh_" FROM "table_2780146_6" WHERE "1.23" = "hc__g_kwh_"