Has there ever been a 6–5 in the La Liga?

Yes, 1 time.

The only time: September 16, 1951, Espanyol beat Real Zaragoza (Real Zaragoza 5–6 Espanyol).

Nearby scores

1. 7–4 2 times
2. 7–5 1 time
3. 7–6 Never
4. 6–4 10 times
5. 6–5 1 time
6. 6–6 1 time
7. 5–4 31 times
8. 5–5 2 times