human
Considering the provided database schema and associated query, produce SQL code to retrieve the answer to the query. 
###Database Schema: Polling Firm, Date, PSD - PC, UDMR, Elena Băsescu, Others, Undecided
###Question: When the other is n/a and the psc-pc is 30% what is the date?
gpt
SELECT Date FROM table WHERE Others = n/a AND PSD - PC = 30%