Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_2780146_6 ( no_x__g_kwh_ VARCHAR, hc__g_kwh_ VARCHAR )

### Question ###
What's the NO of the standard with HC of 1.23 g/kWh?

### Accurate SQL ###

SELECT no_x__g_kwh_ FROM table_2780146_6 WHERE hc__g_kwh_ = "1.23"